The invention relates to a microfluidic analysis device, which comprises a capillary substrate, a cover substrate adjacent to a cover side of the capillary substrate and/or a bottom substrate adjacent to a bottom side of the capillary substrate, a capillary structure with at least one capillary, forming a hollow channel, in the interior of the capillary substrate and/or at the interface of the capillary substrate with the cover substrate and/or at the interface of the capillary substrate with the bottom substrate and also a fluid-conducting arrangement for conducting a fluid through the capillary structure, and relates to an associated manufacturing method.
In the chemical, biological and pharmaceutical industry, so-called high-throughput analyzers are in use, capable of carrying out up to 100 000 analyses a day by an automated combination and linkup of processing stations. The stations serve for the handling, dispensing, mixing, analyzing, incubating and/or selecting of samples. However, such analyzers typically involve relatively high procurement and maintenance costs, a high space requirement, a high consumption of reagents and personnel-intensive operation. In order to achieve improvements here, efforts are increasingly being made to replace parts of this analysis process chain by droplet handling in microfluidic structures. These systems include capillary structures that are physically or chemically etched into a base material such as glass or silicon.
In the article by H. M. Joensson and H. Andersson Svahn, Droplet Microfluidics—A Tool for Single-Cell Analysis, in the journal Angew. Chem. Int. Ed. 2012, 51, pages 12176-12192, a description is given of such a microfluidic capillary system of which the functional elements are passively operated within narrow process windows by means of partial pressure differences and special capillary geometries. Complex process procedures, such as brief suspension of fluid streams, volume-regulated admixture of fluids or specific individual separation of partial streams, are not possible with this technique.
Such microfluidic capillary systems may be assigned an optical sensor system, for example for fluorescence measurement, which is conventionally located outside the capillary system, see for example the conference paper by Agresti et al., Ultrahigh-throughput screening in drop-based microfluidics for directed evolution (Supporting information), Proc. of the Nat. Acad. of Science of the United States of America (PNAS), volume 107, no. 9 (2010), pages 4004-4009. However, this arrangement does not allow a direct analysis of fluids by means of direct contact of the optical sensor system with the fluid, and consequently leads to poorer detection and the need for more complex equipment.
What is more, in the conventional microfluidic analysis devices, the way in which they are produced means that it is usually not possible to perform electrical analyses of the fluids within the capillaries. On account of the sensitivity of the materials to chemical or physical etching methods that are used, it is also not usually possible to carry out a structuring of the capillary system, sensors and actuators of different materials by the same method without them influencing one another. Furthermore, it is not usually possible to integrate or structure sensor and actuator elements that consist of different materials than the substrate material of the capillary system in the capillary wall in a fluid-tight manner. This significantly restricts the choice of sensor and actuator principles that can be used.
It is an object of the invention to provide a microfluidic analysis device and a method for the manufacturing thereof by which the difficulties explained above of conventional microfluidic analysis devices and corresponding manufacturing methods can be at least partially avoided.
The invention achieves this object by providing a microfluidic analysis device comprising a capillary substrate, at least one of a cover substrate adjacent to a cover side of the capillary substrate and a bottom substrate adjacent to a bottom side of the capillary substrate, a capillary structure with at least one capillary, forming a hollow channel, in the interior of the capillary substrate or at the interface of the capillary substrate with the cover substrate or at the interface of the capillary substrate with the bottom substrate and a fluid-conducting arrangement for conducting a fluid through the capillary structure, wherein the fluid conducting arrangement is designed for compartmenting the fluid by means of controlled pressure pulses, as well as by providing a method of manufacturing such microfluidic analysis device.
The invention achieves this object also by providing a microfluidic analysis device comprising a capillary substrate, at least one of a cover substrate adjacent to a cover side of the capillary substrate and a bottom substrate adjacent to a bottom side of the capillary substrate, a capillary structure with at least one capillary, forming a hollow channel, in the interior of the capillary substrate or at the interface of the capillary substrate with the cover substrate or at the interface of the capillary substrate with the bottom substrate and a fluid-conducting arrangement for conducting a fluid through the capillary structure, wherein a linear sensor element is integrated in the microfluidic analysis device and extends at least one of along a capillary of the capillary structure and toward the capillary and away from it, and lies with a fluid contact end and at least an adjacent part of its feed in an identical plane to the capillary, said linear sensor element finishing with its fluid contact end flush with a side wall of the capillary or extending into the hollow channel thereof, as well as by providing a method of manufacturing such microfluidic analysis device.
According to a corresponding aspect of the invention, the fluid-conducting arrangement of the microfluidic analysis device is designed for compartmenting the fluid by means of controlled pressure pulses. Therefore, no special capillary geometries need be provided for this purpose. The fluid conduction by means of controlled, and consequently actively produced, pressure pulses also allows much better fluid conduction, and in particular fluid compartmentation, than is possible with complex special capillary geometries and passive partial pressure differences.
In a further aspect of the invention, a linear sensor element, which extends toward a capillary of the capillary structure and/or away from it or along the capillary, and the end of which and at least an adjacent part of its feed lie in an identical plane to the capillary, is integrated in the microfluidic analysis device. In this case, the linear sensor element finishes with a fluid contact end flush against a side wall of the capillary or extends into the hollow channel thereof. This makes it possible that, during operation, the linear sensor element comes into contact at its fluid contact end directly with the fluid flowing in the capillary, whereby the sensor behavior can be much improved in comparison with sensors arranged outside the microfluidic analysis device.
In a development of the invention, the linear sensor element is an optically conducting wire material, for example an optical waveguide, or an electrically conducting wire material. As a result, optical and/or electrical sensors for the fluid analysis can be provided in the desired way in a form that is integrated in the microfluidic analysis device.
In a development of the invention, the fluid conducting arrangement is designed for providing the pressure pulses with pressures of up to 10 bar and pulse widths of between 1 μs and 10 s. This allows in particular a reliable compartmentation of the fluid with a high throughput, i.e. a high number of fluid compartments or fluid segments per unit of time.
In a development of the invention, the fluid conducting arrangement has one or more activatable valves integrated in the cover substrate and/or in the bottom substrate for opening and closing a respective capillary of the capillary structure. Consequently, such valves that control the fluid conduction are then also integrated in the microfluidic analysis device.
In an advantageous development of the invention, the microfluidic analysis device comprises at least two modules from the group consisting of a compartmentation module, a fluid admixing module, an incubator module, a fluid analysis module and a selection module. As a result, a structurally compact combination of two or more such modules can be achieved as a single component part in the microfluidic analysis device.
In a development of the invention, the microfluidic analysis device has a compartmentation module and/or a fluid admixing module with a first capillary and a second capillary, entering the first capillary at an acute angle, and the fluid conducting arrangement is designed for the pressure-controlled conducting of a first fluid in the first capillary and a second fluid in the second capillary. As a result, the two fluids can be compartmented very exactly and with a high cycle rate in the form of individual fluid segments, or brought together to form a mixed fluid.
In a development of the invention, the microfluidic analysis device has a selection module with an analysis fluid capillary and a selection fluid capillary crossing the latter, and the fluid conducting arrangement is designed for selectively decoupling individual analysis fluid segments from the analysis fluid capillary by corresponding pressure-controlled conducting of a selection fluid in the selection fluid capillary. This allows the specific separation of individual analysis fluid segments from a segmented analysis fluid stream by means of suitable active pressure pulses on the selection fluid.
In a development of the invention, the microfluidic analysis device has one or more magnetic coils as a respective sensor or actuator, the coil being integrated in or on the capillary substrate. Using such a magnetic coil and magnetic particles in a fluid conducted in the capillary allows for example the flow conditions and process conditions within the capillary structure to be controlled or monitored in a desired way.
With the method according to the invention, a microfluidic analysis device according to the invention can be advantageously produced in such a way that at least one capillary of the capillary structure is formed by a step of machining the capillary substrate and/or the cover substrate and/or the bottom substrate. This is found to be advantageous in comparison with other conventional capillary structure producing techniques, in particular with regard to complexity and the flexibility of the materials used.
In a refinement of the method according to the invention, with the forming of the capillary structure by the machining step, a previously formed linear sensor element that crosses the capillary or protrudes into it is cut open or structured on one side, i.e. cut off, in the region of the capillary. As a result, a sensor element of which the fluid contact end finishes flush with the side wall of the capillary or extends in the hollow channel thereof, and in this way can come into contact directly with the fluid conducted through during operation, can be provided very reliably.